Haematological and biochemical alterations in leprosy patients already treated with dapsone and MDT

Hematological alterations in lepromatous leprosy: A cross-sectional observational study

BACKGROUND

Dapsone has been the mainstay for the treatment of leprosy since its discovery in the 1940s. However, hematological disturbances are not uncommon in leprosy patients on daily dapsone therapy. Hence, the present study was conducted to document the hematologic alterations observed in lepromatous leprosy patients treated with Dapsone 100 mg daily.

METHODOLOGY

A cross-sectional observational study was conducted amongst 32 lepromatous leprosy patients treated with Dapsone 100 mg daily. A complete hemogram was conducted for all the study recruits. The test results were compared against the standard average values for adults for the given variables. The one sample t-test was employed to compare the difference between the study values and the standard normal values for adults. The statistical significance was considered at p < 0.05.

RESULTS

The study reveals a marked decrease in hemoglobin concentration in patients on dapsone, 100 mg daily. Other hematological alterations found were reduced platelet count, reduced mean platelet volume, reduced Hematocrit, reduced Mean Corpuscular hemoglobin, reduced Mean Corpuscular hemoglobin concentration. (p < 0.05).

CONCLUSION

Treatment of lepromatous leprosy with 100 mg daily Dapsone therapy may lead to hematological alterations. These findings are suggestive of dapsone-induced hemolysis.

Clofazimine-induced methemoglobinemia: A rare incidence

Clofazimine is commonly used for the treatment of leprosy and chronic use of it can lead to methemoglobinemia, which is a rare but major concern. Iron of hemoglobin remains in the form of ferric (Fe3+) in methemoglobinemia as compared with ferrous form (Fe2+) in normal situation. This transformation prevents oxygen carriage and results in higher level of MetHb in blood which could be dangerous to life. In normal patients the level of MetHb is <1%. We report a case where acute ingestion of many tablets of clofazimine resulted in methemoglobinemia. Cyanosis was not apparent in this case leading to delayed diagnosis, and despite >30% MetHb levels, the clinical presentation was not very suggestive. Because of the nonavailability of intravenous methylene blue and parenteral ascorbic acid, tablet ascorbic acid was used for the management. Gradual decrease of MetHb levels was observed, with amelioration of symptoms and improvement in patient's condition. Review of the literature failed to reveal publication of acute methemoglobinemia with such presentation in the past. Awareness about possibility of methemoglobinemia and its possible contributors will help primary care physician and emergency physician suspect this condition early in patients presenting with history of unknown drug overdose and work in proper direction.

Clinical oxidative stress during leprosy multidrug therapy: impact of dapsone oxidation

This study aims to assess the oxidative stress in leprosy patients under multidrug therapy (MDT; dapsone, clofazimine and rifampicin), evaluating the nitric oxide (NO) concentration, catalase (CAT) and superoxide dismutase (SOD) activities, glutathione (GSH) levels, total antioxidant capacity, lipid peroxidation, and methemoglobin formation. For this, we analyzed 23 leprosy patients and 20 healthy individuals from the Amazon region, Brazil, aged between 20 and 45 years. Blood sampling enabled the evaluation of leprosy patients prior to starting multidrug therapy (called MDT 0) and until the third month of multidrug therapy (MDT 3). With regard to dapsone (DDS) plasma levels, we showed that there was no statistical difference in drug plasma levels between multibacillary (0.518±0.029 µg/mL) and paucibacillary (0.662±0.123 µg/mL) patients. The methemoglobin levels and numbers of Heinz bodies were significantly enhanced after the third MDT-supervised dose, but this treatment did not significantly change the lipid peroxidation and NO levels in these leprosy patients. In addition, CAT activity was significantly reduced in MDT-treated leprosy patients, while GSH content was increased in these patients. However, SOD and Trolox equivalent antioxidant capacity levels were similar in patients with and without treatment. These data suggest that MDT can reduce the activity of some antioxidant enzyme and influence ROS accumulation, which may induce hematological changes, such as methemoglobinemia in patients with leprosy. We also explored some redox mechanisms associated with DDS and its main oxidative metabolite DDS-NHOH and we explored the possible binding of DDS to the active site of CYP2C19 with the aid of molecular modeling software.

Efficacy and safety of dapsone as a second-line treatment in non-splenectomized adults with immune thrombocytopenic purpura

In adults with immune thrombocytopenic purpura (ITP), steroids are usually proposed as first-line therapy, but long-term complete responses are obtained in no more than 20% of patients. For the remaining patients, splenectomy is considered the treatment of choice, with reported "cure" rates from 60-70%. However, the inherent risks of surgery and sepsis after splenectomy without a guarantee of success justify the search for strategies aimed to avoid splenectomy. Here we retrospectively evaluated the results of dapsone treatment in ITP patients that failed first-line therapy with steroids. These patients received dapsone 100 mg/day for a minimum of 30 days before splenectomy was considered. Efficacy was defined as a sustained rise in platelet counts (>50 x 10(9)/l) clearly attributed to dapsone treatment. Among 52 steroid-dependent or refractory patients, dapsone resulted in sustained increases in platelet counts in 44.2% of patients, after a median follow-up of 21.10 months after treatment initiation. The long-term efficacy of dapsone in this setting is further corroborated by the observation that none of the "responding" patients required splenectomy in the follow-up, compared to 69.0% of the "non-responding" patients. Dapsone-related adverse events were mild and promptly reversed by treatment withdrawal. The results of our retrospective analysis suggest that dapsone is a safe and effective second-line agent for steroid-dependent or refractory ITP patients. Because of its well-known safety profile and low cost compared to other potential second-line treatments for ITP, a trial course of dapsone should be viewed as an attractive option before splenectomy in steroid-dependent of refractory adult ITP patients.

Effects of H(2)-receptor antagonists on dapsone-induced methaemoglobinaemia in rats

Dapsone (DDS) (4,4'diaminodiphenylsulfone), the drug of choice for the treatment of leprosy, frequently induces haemolytic anaemia and methaemoglobinaemia. N-hydroxylation, one of the major pathways of biotransformation, has been constantly related to the methaemoglobinaemia observed with the use of the drug. In order to determine the reversible inhibition of this toxicologic bioactivation pathway without changing the detoxification pathways of the drug or cytosolic acetylation, cimetidine (CIM), ranitidine and famotidine were administered in combination with DDS to male Wistar rats weighing 200-220 g. The animals were divided into nine groups of eight: group 1 received a single dose of 40 mg kg (-1) DDS in dimethylsulfoxide (DMSO) and groups 2-4 received the same treatment as group 1 but after the administration of a single dose of 100, 150 and 200 mg kg (-1) CIM, respectively, injected 2 h prior DDS administration. Groups 5-9 received the same treatment as group 2 but after the treatment of ranitidine (50 and 100 mg kg (-1) intraperitoneally (i.p.) in 200 microl DMSO) and famotidine (10, 50 and 100 mg kg (-1) i.p. in 200 microl DMSO), respectively. The animals were then anaesthetized with ether and blood was collected from the aorta for the determination of plasma DDS and monoacetyldapsone concentrations by HPLC and later for the determination of methaemoglobinaemia by spectrophotometry. CIM showed a higher affinity for cytochrome P-450 than famotidine and ranitidine. The results obtained showed the potentiality of the pharmacological effects of DDS with a low risk of adverse reactions, especially methaemoglobinaemia, which is dose dependent.

Immunohematotoxicity studies with combinations of dapsone and zidovudine

We investigated the immunohematoxicities of the antiparasitic drug dapsone (DDS) and the antiretroviral drug zidovudine (ZDV, AZT) given alone or in combination in BALB/c mice. DDS is used for prophylaxis and treatment of Pneumocystis carinii infection in AIDS patients. We examined the impact of concurrent administration of these drugs on the immune and hematopoietic systems because DDS causes hematotoxicity and ZDV therapy results in bone marrow toxicity. Daily oral administration of DDS at 25 and 50 mg/kg for 28 days caused a slight anemia, marked methemoglobinemia, reticulocytosis, and a moderate leukopenia (P < 0.01 for all parameters) but had no discernible effect on platelet count. In DDS-treated mice, the proliferative response of splenic T cells to concanavalin A was > or = 35% higher than that manifested by splenocytes from vehicle-treated control mice. ZDV at 240 and 480 mg/kg was not immunosuppressive but caused low-grade macrocytic anemia, thrombocytosis, and neutropenia; these effects were drug dose-dependent and statistically significant (P < 0.01). Concurrent administration of DDS and ZDV augmented the severity of ZDV-mediated macrocytic anemia, and 7 of 12 (58%) mice did not survive treatment with the high doses of DDS and ZDV (50 and 480 mg/kg, respectively). On the other hand, co-administration of ZDV mitigated DDS-induced methemoglobinemia and the DDS-associated elevation in lymphoproliferative response. These data suggest interaction between DDS and ZDV in mice and indicate a need for caution in using DDS as long-term therapy in AIDS patients receiving ZDV.